sets but then sounds

[Sally363]

It's 9427. Until today it worked. I set it, the beeps sounded and then it set.
when I came back I opened the front door, the alarm sounded and I put in the code and it stopped.
Today when I set it, the beeps sounded and when they finished the alarm immediately went off, inside only. The outside bell was not triggered
what's gone wrong and how do I fix it?

 

[sparkymarka]

It didn’t set ….it was an exit fault …stay by the keypad when you set the alarm don’t move see if any zone lights are on ..

 

[Sally363]

The wind took the door and slammed it shut. A bit of insulation fell off the frame. When I tried to set the alarm, the sound was continuous, no zone lights came on and the fault was cured
many thanks to all